1. Technical Field
The present invention relates to a liquid ejecting head module that includes a liquid ejecting head for ejecting liquid through a nozzle aperture and a liquid ejecting apparatus and, more particularly, the invention relates to an ink jet recording head module and an ink jet recording apparatus.
2. Related Art
A liquid ejecting apparatus typified by an ink jet recording apparatus such as an ink jet printer, an ink jet plotter or the like includes a liquid ejecting head that is capable of ejecting a liquid such as ink or the like contained in an ink cartridge, an ink container or the like as liquid droplets.
Regarding the liquid ejecting head used as a single unit for the aforementioned liquid ejecting apparatus, it is difficult to extend nozzle apertures, i.e., increase the number of nozzle apertures, and to achieve high-density nozzle apertures due to the increased manufacturing cost thereof as well as impairment of yield thereof in a manufacturing process that is caused by an increase in size thereof. In view of such circumstances, e.g., WO 2004/022344 discloses a unitized liquid ejecting head unit, hereinafter referred to simply as a head unit, that includes a plurality of liquid ejecting heads held by a holder, which is a common plate therefor.
As regards the aforementioned head unit, an extended row of equally spaced nozzles can be formed in a first direction by staggering the liquid ejecting heads in the first direction. Incidentally, the liquid ejecting heads are staggered on the head unit as described above; more specifically, the plurality of the liquid ejecting heads are disposed side by side in the first direction in which the nozzle apertures are disposed side by side; and two rows formed by the plurality of the liquid ejecting heads disposed side by side in the first direction are further disposed side by side in a second direction that is perpendicular to the first direction in which the nozzle apertures are disposed side by side. The aforementioned two rows of the liquid ejecting heads disposed side by side in the second direction are slightly spaced apart from each other in the first direction. In addition to the above, as regards the two liquid ejecting heads disposed in contiguous relation to each other in the two rows, the nozzle apertures formed at an end of a first nozzle row disposed on a first liquid ejecting head and the other nozzle apertures formed at an end of a second nozzle row disposed on a second liquid ejecting head are configured to be aligned with each other in the first direction. Hereby, with the plurality of liquid ejecting heads, it is possible to consecutively form the nozzle rows by disposing the equally spaced nozzles side by side in the first direction, and it is further possible to perform printing across a wide area by utilizing the width of the consecutive nozzle rows.
Nevertheless, the needs arise for consecutively forming the extended equally spaced nozzle row in the first direction of the head unit to hold the plurality of the liquid ejecting heads to the common holder. However, in a case where any one of the liquid ejecting heads disposed on the head unit becomes faulty, it is necessary to dismount the head unit that has a faulty liquid ejecting head from the liquid ejecting apparatus and replace the faulty liquid ejecting head with a new one; as a result of the above, a problem of performing a complicated replacing process on the faulty liquid ejecting head arises. Incidentally, each liquid ejecting head of the head unit is connected to a liquid supplying tube, an electrical wiring or the like, and therefore, it is difficult to dismount only one faulty liquid ejecting head directly from the liquid ejecting apparatus. In addition, a new liquid ejecting head that replaces the faulty liquid ejecting head should be positioned relative to the nozzle apertures of the other liquid ejecting heads with high precision. Accordingly, it is necessary to dismount the head unit integrally formed with the plurality of the liquid ejecting heads, in which the faulty liquid ejecting head lies, from the liquid ejecting apparatus and replace the faulty integral head unit with a new one.
In addition to the above, the extended nozzle row that is extended beyond the length of the head unit without being limited to the length of the nozzle row on a single head unit is made possible by disposing the plurality of head units side by side and modularizing the plurality of head units without mounting numerous liquid ejecting heads on the single head unit. However, a problem concerning the aforementioned description is an increase in size of a head module in the second direction that is perpendicular to the first direction due to the head units having to be staggered in order to configure the nozzle row, in which the equally spaced nozzle apertures are disposed consecutively in the first direction.
Further, the nozzle rows of the head module, which have an increased size in the second direction, are disposed at a different position from each other in the second direction, therefore, another problem is that printing quality is impaired due to a deviation in a timing when liquid droplets, such as ink droplets, land on a recording medium to be printed and a color-difference caused by a difference in an amount of smearing of liquid on the recording medium to be printed.
The problems as described above exist in not only a head module provided with an ink jet recording head that ejects ink but also a liquid ejecting head module with a liquid ejecting head that ejects a liquid other than ink.